Construction for heat-transfer reduction



Dec. 12, 1944. c, DURHAM 2,364,961

CONSTRUCTION FOR HEAT-TRANSFER REDUCTION Filed May 27, 1941 .lrwvefitor. Clyde Durham,

His Attorney- Patented Dec. 12, 1944 CONSTRUCTION FOR HEAT- TBAQ ISFER REDUCTION Clyde Durham, Schenectady, N. Y., asslgnor to General Electric Company, a corporation of New York Application May 27, 1941, Serial No. 395,415

5 Claims. (Cl. 154-45) The present invention relates to elastic fluid turbine arrangements and is of particular interest in arrangements including a high pressure turbine and a double-flow, low pressure turbine connected by a cross-over conduit whichhas a common wall with the exhaust casing oi the double-flow turbine. In arrangements of this kind it is important to reduce the heat-transfer from the fluid carried in the cross-over conduit to the fluid contained in the exhaust casing.

The object of the invention is to provide an improved construction and arrangement of this kind whereby the heat-transfer from the crossover conduit to the fluid contained in the exhaust casing is substantially reduced.

For a consideration of what I believe to be novel and my invention, attention is directed to the following description and the claims appended thereto in connection with the accompanying drawing,

In the drawing, Fig. 1 is a perspective view, part-1y broken away, of a turbine arrangement embodying my invention; Fig. 2 is a sectional view of the arrangement in Fig. 1; and Fig. 3 is an enlarged detail view of a part of Figs. 1 and 2.

The turbine arrangement shown in the drawing comprises a high pressure turbine l and a low pressure, double-flow turbine ll having an exhaust hood or casing I2 and an inlet l3. Elastic fluid discharged from the high pressure turbine I0 is conducted to the inlet 13 of the low pressure, double-flow turbine H by a cross-over conduit or channel It. The cross-over conduit H in the present arrangement is fabricated and has a wall l5 formed by or common with the exhaust hood or casing ii of the low pressure, double-flow turbine.

A more detailed description of the arrangement so far described is tound in the patent to O. Junggren, No. 2,102,416, issued December 14, 1937 and assigned to the same assignee as the present application.

During operation, fluid discharged from the high pressure turbine III is conducted by the cross-over conduit is to the inlet l3 of the low pressure, double-flow turbine, whence portions of the fluid flow in opposite directions through the two parts of the double-flow turbine and are dis charged therefrom into a chamber I6 formed by the exhaust hood or casing l2. As pointed out above, it is important to reduce heat-transfer from the fluid contained in the cross-over conduit ll through the wall I! to the exhaust fluid contained in the chamber l6 because such heattransfer would raise the temperature and presother portions 23 of the pins may be considered sure of the exhaust fluid and thereby affect the.

operation and the emciency of the double-flow turbine.

The heat-transfer is reduced by the provision of lagging which in accordance with my invention is loosely attached to the inner surface of the wall 15. In a preferred embodiment the lagging is formed by a sheet or sheets of metal spaced from and loosely secured to the inner surface of the wall l5 inside the chamber It. The loose attachment permits relative movement between the lagging and the wall l5 as may occur due to different expansions of the lagging and the wall during operation. An important feature of my invention is the particular construction of the attaching means for the lagging and the method of assembly of the lagging on the wall if).

The lagging comprises a plurality of overlapping sheets ll of metal each having a plurality of spaced openings i 8. A plurality of pins or supporting and attaching members IS in the form of flanged cylinders are secured by welds 20 to the common wall l5 of the cross-over conduit and the exhaust hood 12. Each pin has an end portion or flange 2| forming a shoulder 22 for engaging the lagging ii. Another end portion 23 of each cylinder projects loosely through one of the openings 18 of the sheet 11 and is rolled over or expanded or flared to secure the sheet H to the cylinder. Preferably a washer 24 is provided between and engages both the expanded end portion 23 and the sheet ll. The openings !8 of the sheet I! and the end portions 23 of the supporting cylindersform annular clearances 25 to permit relative movement between the wall l5 and the sheet II.

During assembly, one cylinder 19 is inserted into each opening of the sheet H with the shoulder 22 engaging one side of the sheet 11. The washer 24 then is inserted and placed onto the opposite side of the sheet l1. Thereupon the free end portion 23 of the cylinder 19. is conically expanded to engage the washer 24 and to form a snug flt between the lagging sheet and the washer.

After assembly of the cylinders on the sheet a unitary lagging unit is formed which thereafter is secured to the exhaust hood by the provision of the welds 20. These welds, as shown in the drawing, are formed between the inner suriace of the cylindrical supporting pin and the wall i5.

From another viewpoint, the cylindrical supporting pins, more particularly the end portions or flanges 2| thereof, constitute spacer rings between the laggin sheet l1 and the wall 15. The

cylindrical extensions formed on the inner walls of the s er rings II which project through openings' in the sheet I! and have outer ends rolled over or expanded on the side of the sheet ll opposite the spacer ring 2|. The provision of spacer rings with cylindrical extensions projecting through openings of the lagging sheet permit assembly of the spacer rings with the sheet to form a compact unit or a lag ng arrangement. The provision of spacer rings facilitates the welding of the lagging arrangements to a wall. The inner diameter of the spacer rings or cylindrical supporting and attaching pins must be large enough relative to their length to permit the insertion of a weldinzeiectrode and the formation of the weld 20 between the insides of the spacer ring and the wall I 8.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. The combination of a metallic wall, a sheet of lagging having a plurality of openings, and means for supporting the sheet on and spacing it from the wall, said means comprising a plurality of hollow cylindrical supporting pins, a weld fusing the inside of each pin to the wall, each pin having a shoulder engaging the sheet and the outer end of each pin projecting loosely through an opening and being flared.

2. The combination of a metallic wall, a sheet of lagging having a plurality of openings, and means for supporting the sheet on and spacing it from the wall, said means comprising a plurality of hollow cylindrical supporting pins, each pin having a reduced flared outer end portion loosely projecting through an opening of'the sheet and having a shoulder engaging the sheet, and a weld formed inside the cylindrical pin and fusing it to the wall.

3. Lagging arrangement comprising a sheet of lagging having a plurality of openings, and means for loosely supporting the sheet when attached to a wall comprising a plurality of cylindrical pins each having a shoulder engaging the sheet and having an end portion loosely projecting through one of the openings and being expanded, and a washer between the expanded portion and the sheet.

4. A housing having a metallic wall, a sheet of lagging having a plurality of openings, and means for spacing the sheet from the wall and supporting it thereon to reduce heat-transfer through the wall, said means comprising a plurality of spacer rings, means loosely connecting the rings to the sheet in alinement with the openings therein, and welds fusing the inside only of each ring to the wall.

5. The combination of a metallic wall, a lagging arrangement supported thereon and including .a sheet having a plurality of openings, at hollow cylinder for each opening having a flange disposed between and engaging the wall and one side of the sheet and having a flared end portion adjacent the other side of the sheet, and welds securing the inside of the cylinders to the wall.

' CLYDE DURHAM. 

